I did some testing to see what was going on in this last thing. The map{} version produces different results because somehow it appears that it is modifying the map{} input!

I don't understand WHY? either, I didn't think that map{} could modify an input, but evidently that is true when the $_ var is modified. This modified input apparently is used on subsequent use of the map{}.

My testing raises more questions than it provides answers, but one thing is that ("a","b","c","d") is different than ('a'..'d').

I changed to a,b,c for input instead of 1,2,3 during testing to differentiate the "for (1..2)" from the map's 1,2.

Anyway I hope looking at this test will stimulate other Monk brain cells! 

#!/usr/bin/perl -w
use strict;
$| =1; #autoflush on (sequence STDERR STDOUT timewise)

foreach my $z (1..3)
{
   my @a = map{ $_++} ('a'..'d');
   print "z=$z variable a=@a\n";
}

#prints
#z=1 variable a=a b c d
#z=2 variable a=b c d e
#z=3 variable a=c d e f

foreach my $z (1..3)
{
   #for some reason this modifies the input to the map
   #
   my @a = map{ $_++} ("a","b","c","d");
   
   #this works differently....ie, like the 2nd case in post!
   # my @a = map{my $x = $_;
   #                $x++;} ("a","b","c","d");

   print "z=$z variable a=@a\n";
}
#prints
#Modification of a read-only value attempted at 
#C:\TEMP\perl11.pl line 18.

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In reply to Re^2: list assignment and undef (range returns non-temps) by Marshall
in thread list assignment and undef by ig

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